Sound-responsive device



Feb. 28,1928. 1,660,990

H. F. DCDGE SOUND RESPONSIVE DEVICE Filed Deo. 30. 1921 l24 I Z3 .1f

" 'ff/Mm l Patented Feb. 2s, 192e.V

. 1.660.990-n UNITED sTATr-:sf -PATENr-OFFICE.

HAROLD F. DODGE, F NEW YORK, N. Y., ABSIGNOR TO wnsrmm ELECTRIC comm,

INCORPORATED, 0F NEW YORK, N.,.Y., A CORPORATION 0F NEW YORK.

BOUND-RESPONSIVE DEVICE.

Application led 'December 30, 1921. Serial No. 525,898.

This invention relates to tele honic or similar apparatus employingfa iaphra adapted to be actuated: in accordance wlth sound waves. `More speciicall the invention relates to a mounting an controlling means for the diaphragm.

It is an object of this invention to provide a vi'bratory system which is substantially aperiodic and therefore,.substantially equally responsive tov different frequencies of the sameA intensities. p The means for mounting the diaphragm `loosely lsupports it in the static state, butrallows it to vibrate as a whole in the dynamic state and controls its vibrations through the dynamic action of air films. Another object of this invention is to providel an efficient device of'the above t e which is simple in construction and capab e of giving high quality in the sounds being transmitted 'or repro uced. l.

In general the invention provides means for controlling the vibration of and for mounting the diaphragm, consisting of air films between a plurality of thin annular members or washers of 'light material lo-4 cated at the periphery of the diaphragm and on each side thereof. v

A specific application of the inyentiomdescribed more fully hereinafter, comprises telephonie apparatus lof lthe resistance varying type vsuch as a telephone transmitter,

A cylindrical shell 3, flanged atone endA and internally threaded at the other, sup-A ports therein an. annular insulating member 4, partly covering the interiorof` the shell and havingv a flanged portion artly closing the opening in the flanged end) of the shell. Completing the closure isa disc 5, having a Banged edge internally and externally threaded. The external threads engage threads on the insulator 4 tov supportthe dlsc 1n position, and the internal threads secure the annular electrodey 6, which is insulated from the shell by means ofthe insulating member/1. 'The' inner surface ofL disc 5 is preferably covered by a suitable insulating material Against electrode 6 and projecting into the interior of the -chamber is an annular barrier 7 of insulating material. `Disposed 'adjacent to barrier 7 is a second electrode 8 in contact withv shell'3. Against electrode 8 is al number of very thin washers 9 made of paper or alumid num foil. aluminum,

sulating material .24, is loosely supported when in. the static state yagainst theser washers by a number Yof similar washers 1l,

A diaphragm 10, preferably of. having one side coated with in.

spacerY ring 12,^ and clamping ring 13. t When the clamping ring 13- isvsecured in.v

position, the space provided for the washers and the diaphragm is slightly greater than the combined thickness of all the washers andthe diaphragm thus loosely supporting the diaphragm when in the static state between the two banks n of washers. These washersl may be crimped so as to provide `a thin air space between adjacent washers,

usually the warping or irregularities produced in handling them is sufficient to provide the necessary air spaces. This system of mounting provides a constant elasticity for all displacements of the diaphragm at zero frequency. A small diaphragm thus supported is capable of vibrating at an amplitude comparable with that o fl theo usual large diaphragme employed in transmitters.. This supporting means also provides eifec.

tive air damping for controlling the amplitude of vibration of the diaphragm, and dynamic elasticity `which increases with frequency in such a way as to provide a vibrating system which is substantially aperiodic and equally responsive to vibrations of the different frequencies of the same in tensities. Clamping ring 13 is provided with a recess in whicha'moisture-proof dia-- phragm 14 of varnished linen, or some other suitable moisture-proof material, is supported by means-of a wedge ring 15.

l,As shown in Fig. 1, which illustrates one a plication of the invention,'the transmitter is securedto a mouthpiece 16,which, inturn, is mounted in'acase 17 provided with e member for agitating the carbon within the` The effective a lug for supporting the device on desk stands and wall sets. It is also adaptable to the breast type transmitter employed by switchboard operators, thus producing a much lighter and cheaper device without any sacrifice in efficiency.

y The mouthpiece shown in Fig. 1 is of the multi-reversal type, giving the advantages of a comparatively longer one without its disadvantages. It comprises a bell-shaped cup 16 tothe base of which is secured the transmitter 22. Integral with the cup and projecting within it. is a cylindrical portion 19, which has a conical opening therein communicating with the transmitter. Supported near the other e'nd of the cup 16 by means of a. perforated grid 20 is a second cup 21 inverted with respect to cup 16 and project-ing within it and over the .portion 19. length of the mouthpiece, therefore, is substantially that of the combined lengths of cups 16 and 21 and portion 19.

What is claimed is:

1. A telephone transmitter comprising a carbon containing 'chamber .and a vibratable chamber, and a plurality of washers of thin material located on each side of saidmember at its periphery lto provide a plurality of air films between said washers for controlling the motion of said member.

2. A telephone transmitter comprising a carbon containing chamber and a sound ref sponsive closure for said chamber and means for supporting said sound responsive closure at its periphery, comprising multiple layers of thin material located on each side of said closure and separated by air films, said cloat its periphery to render said diaphragm substantially aperiodic.

4. A telephone transmitter comprising a carbon-containing chamber, a diaphragm closure therefor adapted to vibrate as a whole, a plurality of thin annular members separated by films of air juxtaposed at the periphery of the diaphragm on each side thereof to control its vibrations.

5. A telephone transmitter comprising a carbon-containing chamber, a diaphragm closure therefor, a plurality of annular members of thin material uxtaposed on each side of the diaphragmI at its periphery to form a plurality of air spaces between said annular members for controlling the vibrations of said diaphragm.

6. In combination a light diaphragm capable of vibratin as a'whole and means 'for controlling the vi rationsof said diaphragm comprising a plurality of washers of thin material located on each side of said diaphragm at its periphery to provide a plurality of air films between said washers.

In witness whereof,.I hereunto subscribe mgy 1name this 27th day 0f December A. D. 1 2

HAROLD F. DODGE. 

